Software radio, and putting it in the air.
Alongside client work, Quantum bit runs its own applied research. Our principal programme, AMOS-BL, develops an adaptive modular software-defined radio for unmanned aircraft — RF spectrum monitoring and signal localisation from a flying platform.
Adaptive modular SDR for unmanned aircraft
AMOS-BL — Adaptivni modularni softverski upravljan radio za besposadne letjelice — is a software-defined radio designed from the outset to fly. Rather than adapting ground equipment for airborne use, the system was developed against the constraints that actually govern a UAV payload: mass, volume, available power, antenna placement and vibration.
The radio monitors the RF spectrum and localises signal sources. Its intended applications are border surveillance, control of personnel movement, and logistics support in areas where cellular coverage is weak or absent — situations where knowing that a transmitter exists, and where it is, is the whole problem.
The research covers two configurations: an airborne SDR for precision positioning in border control, and a stationary variant for tracking personnel movement.
What makes an airborne receiver hard
The programme was defined by five constraints that pull against each other. Improving any one of them tends to cost you another.
Receiver sensitivity
Detecting weak emitters from altitude, against a noise floor that a moving airframe and its own electronics keep raising.
Antenna steering
Directing reception from a platform that is itself moving and rotating, without a mechanically prohibitive assembly.
Localisation accuracy
Turning received signals into a position fix precise enough to act on, using active reception methods.
Size and mass
Every gram of payload is endurance the aircraft does not have. Modularity had to be achieved without bulk.
Power budget
Processing-heavy SDR work competes directly with flight time on a single battery.
Integration
RF front end, digital processing, firmware, enclosure and mounting all designed as one system rather than assembled from parts.
Scope and funding
36 months, August 2020 to August 2023.
HRK 4.9 million.
73.53% supported by the European Regional Development Fund, under Croatia's operational programme for competitiveness and cohesion.
RF and analogue design, digital signal processing, embedded firmware, mechanical design and in-house prototyping — the same capabilities we offer clients under general engineering.
Full programme documentation is published at amos-bl.com.
R&D that feeds back into client work
A research programme of this kind is not a side project. It is where the company's harder capabilities get built and proven: signal processing under real noise, firmware written against hardware that does not exist yet, mechanical iteration measured in days because the parts come off our own machines.
Clients who come to us with an engineering problem that spans electronics, software and physical parts are hiring the team that did this, not a team that read about it.
Working on something in this space?
RF, embedded systems, unmanned platforms, or a prototype that has to survive contact with the physical world — we would like to hear about it.